Submitted to: Journal of Chemical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/22/1999
Publication Date: N/A
Interpretive Summary: A chemical compound, called resin glycoside, was isolated from the skin of sweetpotato storage roots. This material was tested at various concentrations to see what effects it had on the survival and development of an insect pest, the diamondback moth. Resin glycosides negatively affected survival and weight gain of diamondback larvae. Even at sublethal concentrations, this chemical delayed developmental time and reduced the number of eggs produced by female moths. Resin glycosides are viewed as an important contributing factor in the development of sweetpotato breeding lines that are resistant to soil insect pests.
Technical Abstract: A resin glycoside material extracted from the periderm tissue of sweetpotato, Ipomoea batatas (L.) Lam., storage roots was bioassayed for its effects on the survival, development, and fecundity of the diamondback moth, Plutella xylostella (L.). The resin glycoside was incorporated into an artificial diet and fed to diamondback larvae. First instars were placed individually into vials containing an artificial diet with one of six concentrations of glycosides (0.00, 0.25, 0.50, 1.00, 1.50, and 2.00 mg/ml). After 6 days, surviving larvae were weighed, sexed, and returned to their vials. Surviving pupae were weighed and incubated at 25oC until moths emerged. Females were fed, mated with males from the laboratory colony, and allowed to lay eggs on aluminum foil strips. There were highly significant negative correlations between resin glycoside levels and survival and between glycoside levels and larval weight after 6 days. No additional larval mortality beyond the sixth day could be attributed to the resin glycoside material. However, there was a significant positive correlation between glycoside concentrations and developmental time of larvae. Lifetime fecundity (eggs/female) also was negatively affected by the resin glycosides at sublethal doses. Resin glycosides are viewed as contributors to resistance in sweetpotato breeding lines to soil insect pests.